Alonso said he'd retire if F1 got to a 25-race calendar, but is doing 28 events this year as he adds a full-season WEC programme to his schedule.

Fernando Alonso is happy to have more sports car races on his schedule than additional Formula 1 grand prix events “because they are more fun” as he juggles two FIA world championship campaigns in 2018.

With F1’s new bosses looking to expand the existing schedule to at least 25 races in the coming years, Alonso said last year he would rather retire from the series than take on such a hectic schedule.

But after signing a deal with Toyota for the FIA World Endurance Championship ‘super season’, including the 24 Hours of Le Mans, plus an appearance in the Rolex 24 at Daytona in January, Alonso is set to have taken part in at least 28 professional races by the end of the year.

“Formula 1 is predictable,” Alonso said. "Formula 1 is about constructors’ championship. There are different teams in different rows of the grid, but there is not much more that the driver can do. That’s the sad thing.

“That’s why the tyre could be a factor [in F1]. The tyres are very good this year. The tyres are performing better than ever. Maybe the tyre is in a way a solution.

“If you spread the compounds and you make creativity into the strategy for the engineers. Maybe that will help the sport that at the moment is a little bit down.”

Alonso’s next sports car duties with Toyota come in early June at the Le Mans test day, which takes place between the upcoming F1 races in Monaco and Canada.